Drop hammer



y 1, 1934- A. SCHNEIDER 1,957,021

DROP HAMMER Filed Dec. 23. 1931 3 Sheets-Sheet l dll Z If,

f i D I I 1 //7venfor':

Mar/may y 1934- A. SCHNEIDER 1,957,021

DROP HAMMER Filed Dec. 23. 1951 3 Sheets-Sheet 2' fllllllllllllll l'l l llllllllllllllm Fig.4

r In venfofi:

A. SCHNEIDER May 1, 1934.

DROP HAMMER Filed Dec. 23. l93l 3 Sheets-Sheet 5 Fig- 8 Fig. 7

/n ven fan I A, ,v gmm 50 of the friction hammer bar 1'.

' Fatented may 11,, 1934 ICE DRQP HAMMER Arthur Schneider, Dusseldorf, Germany, assignor to Eumuco Aktiengesellschaft fiir Maschinenban, German company Leverkusen Schlebusch, Germany,

Application December 23, 1931, Serial No. 582,814 In Germany December 23, 1930 6 Claims.

The present invention relates to a hammer with friction hammer bar, and has for its purpose to extend the life of the bar.

Owing to excessive compressive strain at the moment of striking, these friction hammer bars are often exposed to premature fractures at their base while, at the same time, the high unit pressure prevailing between the friction surface and the driving member causes rapid wear if rolls are employed for driving.

The invention provides a friction bar hammer with a contact surface of finite dimension exceeding the application surface of a roll and disposed between the friction hammer bar and its drivers.

According to the invention, the drivers pressed against the friction hammer bar are moved parallel to the latter and may be secured to endless rotary bands.

One embodiment of the invention is illustrated in the accompanying drawings, in which Figure l is a front View of a drop hammer according to the invention and Figures 2 to 8 are detail views. Referring to the drawings: In the ledges of the standards a the tup b is guided which has a control surface c against which presses the oscillatory lever d which has two arms, its arm d being connected with the key of a rotary valve e by the bar d". The rotary valve e controls the admission of the pressure medium, such as compressed air, to the control cylinder f. The fulcrum of the oscillatory lever d is placed on the standard by means of the two-armed lever z which is moved by a treadle lever y disposed in the anvil block by means of the connecting rod m".

For moving the tup serves the friction hammer bar 1' yieldingly secured thereto by the buffer device 1" and extending into a buffer cylinder A located above the hammer standards. The bar r is firmly connected with the piston B of the cylinder A.

The friction hammer bar 1 is hugged on both sides by two Galls chains n guided by the sprocket pairs q which are constantly rotated by the gears 0-D and E, one of the two gear wheels E being disposed on each shaft of the two upper sprockets q. The pinion C receives its motion from the pulley F. The members of the Galls chains 11 may consist of friction blocks made from a material having a-greater coefficient of friction than that Pressure rolls m disposed in the guides 0 move over the back of the sides of the chains 11. adjacent to the friction hammer bar '1', and the shafts p in the standard a, pass through the guides 0. Each shaft 1) carries a lever k to the end of which an eccentric G is secured.

The eccentricities of the two eccentrics are arranged in different and opposite directions, so that if the levers k strike in the same direction, the eccentrics will turn in opposite directions.

The ends of the levers k are articulated to the rods 1 which can be bent at one of the joints and which are secured to the cross bolt i acting as head of the rod of a piston g which moves in a control cylinder 1. The piston g is actuated on one side by the spring h and on the opposite side by the pressure of a medium, such as compressed air, which is controlled by the rotary valve e.

By means of the rod 11:, the treadle y controls the rotary valve w regulating the admission of compressed air to another control cylinder u 'm which is similar to the control cylinder f and which, by the rods H, acts on the two ,levers '0 also disposed on the standard a, and, by the two eccentrics Z, on thetwo clamping jaws t each of which hugs one side of the friction hammer bar 1. The jaws t are dimensioned and formed so that they will hug in a self-locking manner the friction hammer bar r on its descent when the rods H are in a position of rest, yet loosen themselves automatically when the friction hammer bar r ascends. The jaws t can be tightened only by acting on the rods H by means of the piston of the control cylinder u.

The device functions as follows:

To raise the hammer the rotary valve 6 is opened bya corresponding motion of the treadle 1/ so as to permit the pressure medium to pass to the right side of the control cylinder f, to push the piston g with the bolt 1' and the rods Z to the left and thus press the pressure rolls 111. against the Galls chains 11. by means of the eccentrics G. The chains n are therefore pressed from both sides against the friction bar 1' and cause it to cooperate in their upward motion, the tup b, cushioned by the buffer device 1', following the upward motion of the'bar r, so that the air in the buffer cylinder A is compressed by the piston B. When the tup b has reached the highest desired position, the oscillatory lever d, following the control surface c, has swung so far to the left that the valve e will release the discharge of pressure medium from the control cylinder f. The levers will then return, the rolls m release the chains n,'and the friction hammer bar 1 with the tup b can drop down owing to the weight of the tup and the pressure in the cylinder A.

At the striking moment, the fllCtiOIl hammer bar 1' will be cushioned by the buffer device 1', and the control cylinder u, owing to the motion of the members 2, :c", y, at and w, will also give up its compressed air in. time when the rolls m are released.

By means of the buffer device A and B the descent of the tup b is accelerated in order to attain, in case of relatively small strokes, a more forceful blow than would be possible by a. free fall and, furthermore, to increase the rapidity of succession of the blows. The buffer device 1" serves for reducing the wear of the friction blocks s and protecting the motor against shocks when the pressure rolls are engaged, since it is a matter of experience that the greatest stresses prevail during the lifting of the tup to overcome inertia.

The sheet-like application of the chains n to the friction hammer bar r reduces the pressure per unit of area between the two parts and thus wear to any desired extent.

I claim:

1. In a hammer a friction hammer bar, a tup suspended from said friction hammer bar, two guiding and driving rolls one above the other at each side of said bar, endless rotary bands on said rolls adapted to drive said friction hammer bar and means between said guiding and driving rolls nioved to and fro perpendicularly to the longitudinal direction of said friction hammer bar, said means being adapted to engage periodically the inner side of said bands at a point intermediate the said rolls and to press it against the friction hammer bar.

2. In a hammer a friction hammer bar, a tup suspended from said friction hammer bar, two guiding and driving rolls one above the other at each side of said bar, endless rotary bands constructed as dink-chains on said rolls adapted to drive said friction hammer bar and means between said guiding and drivingrolls moved to and fro perpendicularly to the longitudinal direction of said friction hammer bar, said means being adapted to engage periodically the inner side of said bands at a point intermediate the said rolls and to press it against the friction hammer bar.

3. In a haifimer a friction hammer bar, a tup suspended from said friction hammer bar, two guiding and driving rolls one above the other at eachside of said bar, endless rotary bands on said rolls adapted to drive said friction hammer bar, said bands being provided with friction linings on the side facing the friction hammer bar and means between said guiding and driving rolls moved to. and fro perpendicularly to the longitudinal direction of said friction hammer bar, said means being adapted to engage periodically the inner side of said-bands at a point intermediate the said rolls and to press it against the friction hammer bar.

4. In a hammer a friction hammer bar, a tup suspended from said friction hammer bar, two guiding and driving rolls one above the other at each side of said bar, \endless rotary bands on said rolls adapted to drive said friction hammer bar and means between said guiding and driving rolls moved to and fro perpendicularly to the longitudinal direction of said friction hammer bar, said means being constructed as pressure rolls and adapted to engage periodically the inner side of said bands at a point intermediate the said rolls and to press it against the hammer bar.

5. In a hammer a friction hammer bar, a tup suspended from said friction hammer bar, the connection between the friction hammer bar and the tup being-elastic in the direction of motion, two guiding and driving rolls one above the other at each side of said bar, endless rotary bands on said rolls adapted to drive said friction hammer bar and means between said guiding and driving rolls moved to and fro perpendicularly to the iongitudinal direction of said friction hammer bar, said means being adapted to engage periodically the inner side of said bands at a point intermediate the said rolls and to press it against the friction hammer bar.

6. In a hammer a. friction hammer bar, consisting of metal, a tup suspended from said friction hammer bar, two guiding and driving rolls one above the other at each side of said bar, endless rotary bands on said rolls adapted to drive 115 said friction hammer bar and means between said guiding and driving rolls moved to and fro perpendicularly to the longitudinal direction of said friction hammer bar, said means being adapted to engage periodically the inner side of said bands 120 at a point intermediate the said rolls and to press hammer bar. 

